Coherence

A whole piece of
writing should hang together, or, as one student put it, make
sense. We sometimes describe the speech of someone who is
excited or crazy as "babbling incoherently." What they're saying
probably makes sense to them, but it isn't coherent for the
listener because they're not being told the whole thing in a
reasonable order and with all the pieces of information they
need. This is a common difficulty for writers. Having someone
else who can be objective read your writing, or getting some
distance from it yourself, may help. Other kinds of coherence
problems usually have to do with focus or organization, or both.
Coherence problems can sometimes stem from mechanics as well:
for instance, when the writing isn't consistently in the same
tense, or changes from singular to plural, it is grammatically
incoherent.